1. Field of the Invention
This invention relates to an inductive proximity detector that can be configured to selectively detect ferrous or non-ferrous metal objects.
2. Description of the Related Art
There are many inductive detectors comprising:
a coil forming part of an LC oscillating circuit that generates an oscillation and the inductance of which is sensitive to the presence of a metal object, such that the natural frequency of the oscillating circuit varies as this type of object is brought close, PA0 an oscillator generating a fixed oscillation independent of whether or not the object is present, that forces the oscillating circuit through coupling means, and, PA0 a processing circuit with two inputs, firstly the fixed oscillation signal output from the oscillator, and secondly the variable oscillation signal output from the oscillating circuit and which outputs a detection signal in the presence of the object.
This type of detector, capable of selectively detecting ferrous and non-ferrous metal objects, is described in patent FR-2 716 979.